CAPITOL HILL - Just a week ago, when the Democratic-led U.S. House of Representatives and the Republican-led Senate came back to work after a six-week summer recess, legislative action on gun control seemed possible.

Despite congressional lawmakers' previous passive response to gun violence in the United States, mass shootings in El Paso and Odessa, Texas, and Dayton, Ohio, seemingly galvanized public opinion to a point that Congress could not ignore.

But with just a handful of weeks left in session before the 2020 elections get fully under way, U.S. lawmakers are at an impasse over a compromise that can pass through both chambers of Congress. The impasse is complicated by President Donald Trump's conflicting statements on what measures he would be willing to endorse - and Senate Republican reluctance to act without Trump's blessing.

"We need some guidance from the president about what kind of proposal that would make a difference, that he would actually sign into law," Senate Majority Leader Mitch McConnell told reporters Tuesday. The top Republican senator said Trump's leadership was needed to bring together lawmakers representing urban and rural areas of the country with disparate views on guns.

Senate Democrats plan a late-night marathon of speeches on gun control Tuesday, an echo of past efforts to draw attention to the issue, including House Democrats' June 2016 sit-in following the Orlando Pulse nightclub shooting. The Senate has been sitting on HR 8, the House-passed bill closing loopholes in background checks, since February. Senate Minority Leader Chuck Schumer said it was unlikely to be the option lawmakers settled on.

"HR 8 is the bill that should be on the floor," Schumer, the Democratic leader, told reporters. "We should get a vote on it. Let's see what the Republicans produce. From everything I've been told, it's not going to be even close to HR 8."

McConnell Waiting on Trump to Chart Path on Guns Senate Majority Leader Mitch McConnell says he's waiting for the White House to chart a path forward on gun violence legislation following another mass shooting in Texas

Background checks

If passed, the legislation would require background checks on online, person to person and gun show sales at the federal level.

Trump did sign background check legislation requiring a more thorough reporting of criminal records into law following a series of mass shootings in 2018. But that was under a Republican-majority U.S. Congress.

Now, any bill that passes will have to satisfy both House Democrats heeding cries from their constituents for stricter regulations and Senate Republicans who have long avoided any significant moves on this politically risky issue.

Looming over the deliberations is the influence of the National Rifle Association (NRA) and the possibility Trump will be unwilling to anger the powerful anti-gun-control lobbying group just ahead of his 2020 reelection bid.

House Speaker Nancy Pelosi and Schumer spoke to the president by phone Sunday in an attempt to convince him to get behind their approach.

"We made it clear to the president that any proposal he endorses that does not include the House-passed universal background checks legislation will not get the job done, as dangerous loopholes will still exist, and people who shouldn't have guns will still have access," the Democratic leaders said in a statement afterward.

Senate Republicans have a number of proposals in the works, including a bipartisan offering from Republican Sen. Lindsey Graham and Democrat Richard Blumenthal that would provide states with funding for so-called "red flag" laws.

Democrats have proposed measures that would allow family or law enforcement agents to go to court to keep guns out of the hands of high-risk individuals. Graham told reporters Tuesday his proposal was still in the mix of options before the president.

An overwhelming majority of Americans support such provisions, according to a Washington Post/ABC News poll taken in early September. Eighty-six percent of Americans said they supported implementation of "red flag" laws, while 89% said they supported closing background check loopholes online and at gun shows.

Gun control vs. gun confiscation

Trump has said he is open to reaching a deal with House Democrats on gun control legislation, but "it depends on whether or not the Democrats want to take your guns away, because it's a possibility this is just a ploy to take your guns away or whether or not it's meaningful."

Much of the debate in Washington now centers on a muddied line between gun control and gun confiscation. Democratic presidential candidate Beto O'Rourke, a former House member from Texas, raised the specter of the government confiscating or buying back semi-automatic weapons during last Thursday's debate, and fueled Republican anxiety.

"Hell yes we're going to take your AR-15, your AK-47. We're not going to allow it to be used against our fellow Americans anymore," O'Rourke said. Republicans pounced on his statement as evidence that Democrats were determined to strip Americans of their constitutional, Second Amendment right to own guns.

In the Washington Post/ABC News poll taken days before O'Rourke's pronouncement, 51% of Americans said they trusted congressional Democrats over Trump to handle gun legislation.